Artificial turf for landscape and sports

Abstract

The present invention seeks to provide artificial turf that imitates more closely the root zone, the volume effect, and density of natural grass and that has an improved wear and drainage property. An artificial turf adapted for use in landscape and sports applications comprises a mechanically bounded layer of fibers formed as a non-woven matting made of one or more natural and/or synthetic fibers. A plurality of tufts of pile yarn is inserted through the mechanically bounded layer of fibers. A backing is applied at the backside of the mechanically bounded layer of fibers enhancing anchoring the tufts to the mechanically bounded layer of fibers.

Claims

1. An artificial turf comprising: a mechanically bounded layer of fibers consisting of non-woven matting comprising one or more natural and/or synthetic fibers, and pile yarn inserted through the mechanically bounded layer of fibers, the pile yarn being anchored to the mechanically bounded layer of fibers, wherein the mechanically bounded layer of fibers has a density that decreases from the bottom to the top of the mechanically bounded layer of fibers, and wherein the mechanically bounded layer of fibers is on top of a backing, and the mechanically bounded layer of fibers includes a lower layer an an upper layer, the lower layer being positioned at the bottom of the mechanically bounded layer of fibers and the upper layer being positioned on top of the lower layer, and the upper layer having a higher fiber coarseness than the lower layer.

2. The artificial turf according to claim 1, wherein fill fibers extending the upper surface of the mechanically bounded layer of fibers is created through velour needle-punching, the fill fibers giving the upper surface of the mechanically bounded layer of fibers a velour structure of fibers standing out above the upper surface, thereby providing structural support for the pile yarn by assisting the pile yarn to stand, imitating the root zone of natural grass, and providing cushioning.

3. The artificial turf according to claim 1, wherein the lower layer is a structural layer that is utilized for anchoring the pile yarn and that provides dimensional stability.

4. The artificial turf according to claim 1, wherein the upper layer is a volume simulating layer that acts as a shock-absorbing layer and contributes to a natural feeling of the artificial turf.

5. The artificial turf according to claim 1, wherein the lower layer is formed by fibers that are more flexible and form a denser structure than fibers forming the upper layer, the fibers of the lower layer having a smaller linear mass density than the fibers forming the upper layer.

6. The artificial turf according to claim 5, wherein the fibers of the lower layer have a linear mass density in the range of about 3.3 dtex to about 110 dtex.

7. The artificial turf according to claim 5, wherein the fibers of the upper layer have a linear mass density in the range of about 11 dtex to about 600 dtex.

8. The artificial turf according to claim 1, wherein the mechanically bounded layer of fibers is manufactured as a single fabric or as two separate fabrics that are joined together.

9. The artificial turf according to claim 1, wherein the mechanically bounded layer of fibers is formed by needle-punching.

10. The artificial turf according to claim 1, wherein the mechanically bounded layer of fibers consists of up to eight different types of fibers.

11. The artificial turf according to claim 1, wherein the mechanically bounded layer of fibers, the pile yarn, and the backing enhancing the anchoring of the pile yarn to the mechanically bounded layer of fibers are made of eco-friendly materials that are 100% recyclable by being mechanically deconstructable.

12. The artificial turf according to claim 1, wherein the mechanically bounded layer of fibers, the pile yarn, and the backing are made of 100% polyolefin.

13. A method for manufacturing artificial turf for use in landscape and sports applications, the artificial turf comprising: a mechanically bounded layer of fibers consisting of non-woven matting comprising one or more natural and/or synthetic fibers, and pile yarn inserted through the mechanically bounded layer of fibers, the pile yarn being anchored to the mechanically bounded layer of fibers, wherein the mechanically bounded layer of fibers has a density that decreases from the bottom to the top of the mechanically bounded layer of fibers, and wherein the mechanically bounded layer of fibers is on top of a backing, and the mechanically bounded layer of fibers includes a lower layer an an upper layer, the lower layer being positioned at the bottom of the mechanically bounded layer of fibers and the upper layer being positioned on top of the lower layer, and the upper layer having a higher fiber coarseness than the lower layer; the method comprising the steps of: forming by needle-punching a lower layer from a plurality of natural and/or synthetic fibers; forming by needle-punching an upper layer from a plurality of natural and/or synthetic fibers that have a higher fiber coarseness than the fibers of the lower layer, the upper layer having a less dense structure than the lower layer; placing the upper layer on top of the lower layer to form the mechanically bounded layer of fibers; creating fill fibers extending the upper surface of the upper layer through velour needle-punching thereby giving the upper surface of the upper layer a velour structure of fibers standing out above the upper surface; inserting the pile yarn through the mechanically bounded layer of fibers; and anchoring the pile yarn at the backside of the mechanically bounded layer of fibers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above and other characteristics, features, and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings.

(2) FIG. 1 is a schematic cross-sectional view of the artificial turf in accordance with a first preferred embodiment of the present invention; and

(3) FIG. 2 is a schematic cross-sectional view of the artificial turf in accordance with a second preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(4) The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. Any reference signs in the claims shall not be construed as limiting the scope. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes.

(5) Where the term comprising is used in the present description and claims, it does not exclude other elements or steps. Where an indefinite or definite article is used when referring to a singular noun e.g. a or an, the, this includes a plural of that noun unless something else is specifically stated.

(6) Reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases in one embodiment or in an embodiment in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

(7) Similarly it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

(8) Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

(9) In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures, and techniques have not been shown in detail in order not to obscure an understanding of this description.

(10) The following terms or definitions are provided solely to aid in the understanding of the invention.

(11) The term backside is used herein to denote the side of the mechanically bounded layer of fibers which faces away from the side from which free edges of the tufts stick out.

(12) As employed herein, the term fiber coarseness is defined as weight per fiber length and is normally expressed in units of mg/m or g/m. The fiber coarseness depends on fiber diameter, cell wall thickness, cell wall density, and fiber cross section. A high coarseness value indicates a thick fiber wall, giving stiff fibers unable to collapse. Thin walled fibers with low coarseness value give flexible fibers and a denser structure. The coarser the fibers, the stronger they will be.

(13) As employed herein, the term tex refers to a unit of measure for the linear mass density of fibers and is defined as the mass in grams per 1000 meters. The most commonly used unit is the decitex, abbreviated dtex, which is the mass in grams per 10,000 meters. When measuring objects that consist of multiple fibers the term filament tex is sometimes used, referring to the mass in grams per 1000 meters of a single filament.

(14) As employed herein, the term tufting refers to a type of textile process in which a thread is inserted on a carrier base. Tufted carpets are manufactured by insertion of tufts (a short cluster of elongates strands of yarn attached at the base) through a backing fabric, creating a pile surface of cut and/or loop ends.

(15) As employed herein, the term filament refers to a single continuous strand of natural or synthetic fiber.

(16) As employed herein, the term yarn refers to a continuous strand of twisted or untwisted threads of natural or synthetic material.

(17) As employed herein, the term pile refers to the visible surface (wearing surface) of carpet consisting of upright ends of yarn or yarn tufts in loop and/or cut configuration. Sometimes it is called face or nap.

(18) As employed herein, the term backing refers to a substrate applied to the back of the carpet to increase dimensional stability and enhances the anchoring of the pile yarn.

(19) As employed herein, the term non-woven refers to engineered fabric (sheet or web structure) bonded together by entangling fibers mechanically, thermally, or chemically.

(20) As employed herein, the term needle-punch refers to a mechanical process involving thousands of needles that orient and interlock fibers to create nonwoven fabric.

(21) Referring to FIG. 1, the schematic cross-section of an artificial turf 10 is illustrated in accordance with preferred embodiments of the present invention. The artificial turf 10 includes a mechanically bounded layer of fibers 20, a backing 30, and a plurality of tufts 40.

(22) The mechanically bounded layer of fibers 20 is formed as a non-woven matting made of one or more natural and/or synthetic fibers or yarns. The mechanically bounded layer of fibers 20 serves as a carrier for the tufts 40.

(23) As illustrated in FIG. 1, the mechanically bounded layer of fibers 20 can be a single layer containing a mixture of fibers. According to preferred embodiments of the present invention, the coarseness of the fibers forming the mechanically bounded layer of fibers 20 may increase from the bottom to the top of the layer 20. For example, the coarseness may gradually increase at a constant rate.

(24) Alternatively, as illustrated in FIG. 2, the mechanically bounded layer of fibers 20 can include visually two or more layers, such as, a structural layer 21 and a volume simulating layer 22. The structural layer 21 is positioned at the bottom of the mechanically bounded layer of fibers 20 facing away from the pile yarn 41. The volume simulating layer 22 is positioned on top of the structural layer 21 facing the pile yarn 41. In case of multiple layers of fibers, the mechanically bounded layer of fibers is divided into multiple functionalities, such as, for example, structural enhancements (layer 21) and volume simulating (layer 22).

(25) The mechanically bounded layer of fibers 20 can be manufactured as a single fabric or as two separate fabrics that are joined together. In accordance with preferred embodiment of the present invention, the mechanically bounded layer of fibers 20 is formed by needle-punching. During this mechanical bonding method, fibers are transported with felting needles and interlocked in the non-woven structure. This procedure increases the friction between the fibers, which reinforces the non-woven fabric. To differentiate the structure of the non-woven fabric, the web can be further structured using special machines equipped with structuring fork or crown needles. The surface can be structured as a velour or rib, or with geometrical or linear patterns. Needle-punching is an ecologically friendly technology, as it permits the use of recycled material including that from polyethylene terephthalate bottles and regenerated fibers from apparel, as well as natural fibers. It may be possible to use other technologies to form non-woven fabrics to obtain the mechanically bounded layer of fibers 20.

(26) The mechanically bounded layer of fibers 20 may consist of up to eight different types of fibers. Each of the fibers can have a different color, if desired. The types of fibers can include moisture absorbent fibers, such as coco, cotton, jute, wool, rayon or other natural or synthetic fibers. The types of fibers can further include synthetic fibers, such as polypropylene (PP), polyethylene (PE), polyamides (PA), and polyester (PES) or a combination thereof. The fibers can be treated, for example, with anti-algae, with herbicide, UV-stabilizer, or to be anti-static. The fibers can be melt fibers. The fibers can among others further include mineral based fibers, animal based fibers, or plant based fibers.

(27) If the mechanically bounded layer of fibers 20 is formed as a single layer, as shown in FIG. 1, a mixture of relatively thin walled fibers that are flexible and form a relatively dense structure and, thus, having a relatively low coarseness value and relatively thick walled fibers that are stiff and form a relatively sparse structure and, thus, having a relatively low coarseness value is used in combination. In an exemplary embodiment of the invention, the density of the mechanically bounded layer of fibers 20 can gradually decrease from the bottom to the top of the layer 20. Accordingly, the coarseness of the fibers will gradually increase from the bottom to the top of the layer 20. By designing the mechanically bounded layer of fibers 20 that way, structural support for the tufts 40 and protection for bending points 42 of the tufts 40 is provided as well as shock-absorbance to contribute to a more natural feeling of the artificial turf 10.

(28) If, according to preferred embodiments of the present invention, the mechanically bounded layer of fibers 20 is formed as a single layer, as shown in FIG. 2, the structural layer 21 is formed by relatively thin walled fibers that are flexible and form a relatively dense structure. Accordingly, fibers with the relatively low linear mass density (dtex value) are selected for the structural layer 21. The structural layer 21 is utilized for anchoring the tufts 40. The structural layer 21 provides dimensional stability for the artificial turf 10 and protection for the bending points 42 of the tufts 40. The fibers of the structural layer 21 have preferably a linear mass density in the range of about 3.3 dtex to about 110 dtex, and more preferably of about 11 dtex.

(29) The volume simulating layer 22 is formed by fibers having a larger linear mass density than the fibers of the structural layer 21. The fibers of the volume simulating layer 22 have preferably a linear mass density in the range of about 11 dtex to about 600 dtex, and more preferably of about 110 dtex. Consequently, the volume simulating layer 22 has also a higher fiber coarseness (weight per fiber length) than the structural layer 21. A high coarseness value indicates a thick fiber wall, giving stiff fibers unable to collapse. Therefore, the volume simulating layer 22 of the mechanically bounded layer of fibers 20 is thicker and coarser than the structural layer 21. Fibers with a higher dtex value are selected for the volume simulating layer 22 so that the mechanically bounded layer of fibers 20 can act as a shock-absorbing layer and contribute to a natural feeling of the artificial turf 10.

(30) In addition, the fibers of the mechanically bounded layer of fibers 20 can be given a velour effect by needling to mimic the root zone volume effect of natural grass. Due to a mechanical needling process, fiber is pushed out of the upper surface of the layer 20. Velour needle-punched non-woven material can be produced by placing an non-woven material on a brush-like stitch base and needling of the non-woven material on this stitch base. Since with this method the fibers seized by the needles are needled into the bristles or lamellas of the needle stitch base, the non-woven material needled in this way is given a velour-like appearance where the fiber stands out above the surface.

(31) By velour needle-punching the mechanically bounded layer of fibers 20, fill fibers 23 are created. The fill fibers 23 are punched out of the non-woven fibrous matting of the mechanically bounded layer of fibers 20 creating a natural grass like root zone. The fill fibers 23 give the upper surface of the mechanically bounded layer of fibers 20 (facing the pile yarn 41) a fluffy appearance and provide cushioning. The fill fibers 23 also assist the pile yarn 41 of the tufts 40 to stand. Thus, no infill, as often used with prior art artificial turf, is needed with the artificial turf 10 in accordance with preferred embodiments of the present invention.

(32) Strands of pile yarn 41 form each tuft 40. A tuft 40 is a short cluster of elongates strands of pile yarn 41 attached at the base, the bending point 42. The tufts 40 are inserted through the mechanically bounded layer of fibers 20. Tufting usually is accomplished by inserting reciprocating needles threaded with pile yarn 41 into the mechanically bounded layer of fibers 20 to form tufts 40 of yarn. Loopers or hooks, typically working in timed relationship with the needles, are located such that the loopers are positioned just above the needle eye when the needles are at an extreme point in their stroke through the mechanically bounded layer of fibers 20. When the needles reach that point, pile yarn 41 is picked up from the needles by the loopers and held briefly. Loops or tufts 40 of yarn result from passage of the needles back through the mechanically bounded layer of fibers 20. This process typically is repeated as the loops move away from the loopers due to advancement of the backing through the needling apparatus. Subsequent, the loops can be cut to form a cut pile, for example, by using a looper and knife combination in the tufting process to cut the loops.

(33) The pile yarn 41 can consist of up to four different types of yarns. Each yarn can have a different color, if desired. The pile yarn 41 can be monofilament, tape or a combination thereof. The pile yarn 41 has preferably a linear mass density of about 400 dtex to about 3000 dtex and, more preferably of about 1600 dtex. The number of strands of pile yarn 41 in a tuft 40 is between 2 and 10, and preferably 6. The tuft gauge (distance between rows) is between and 1/16 and typical or 3/16 or . The stitch rate of the tufting is between 8/10 cm and 30/10 cm and preferably 12/10 cm.

(34) In accordance with preferred embodiments of the invention and as shown in FIG. 2, the mechanically bounded layer of fibers 20 may have a height H3 of about 3 mm to about 15 mm, and more preferably about 8 mm. The fill fibers 23 may extend from the upper surface of the mechanically bounded layer of fibers 20 for a height H2 of about 1 mm to about 20 mm, and more preferably of about 10 mm. The pile yarns 41 may extend from the fill fibers 23 for about 1 mm to about 20 mm, and more preferably 10 mm (height H1). The total height H4 of the artificial turf 10 may be about 10 mm to about 60 mm, and more preferably about 28 mm.

(35) The backing 30 is applied to the mechanically bounded layer of fibers 20 as a last finishing step to enhance the anchoring of the tufts to the mechanically bounded layer of fibers 20. In accordance with preferred embodiments of the present invention the backing 30 can be a coated backing such as, for example, a polyethylene (PE) backing that is applied by means of powder or hot melt coating. The backing 30 can further be a calander backing or latex backing.

(36) In the finishing operation, the backside or stitched surface of the mechanically bounded layer of fibers 20 is coated with an adhesive, such as a natural or synthetic rubber or resin latex or emulsion or a powder or hot melt adhesive, to enhance locking or anchoring of tufts 40 to the mechanically bounded layer of fibers 20. Use of such further improves dimensional stability of the tufted turf 10, resulting in more durable turf. Further stabilization can be provided in the finishing operation by laminating, for example, a thermoplastic film or a woven or nonwoven fabric made from polypropylene, polyethylene, or ethylene-propylene copolymers or natural fibers such as jute, to the tufted mechanically bounded layer of fibers 20. The adhesive bonds the mechanically bounded layer of fibers 20 to the backing 30.

(37) To provide an eco-friendly artificial turf 10 in accordance with preferred embodiments of the present invention the mechanically bounded layer of fibers 20, the tufts 40, and the backing 30 may all be made of materials that are recyclable, such as, for example, 100% polyolefin.

(38) Other arrangements for accomplishing the objectives of embodiments of the present invention will be obvious for those skilled in the art. It is to be understood that although preferred embodiments, specific constructions and configurations, as well as materials, have been discussed herein for devices according to the present invention, various changes or modifications in form and detail may be made without departing from the scope and spirit of this invention.